Ixx Journal of Comparative Neurology. 



that the cerebra of dogs poisoned by morphine, choral, or chloroform, 

 exhibited an extremely varicose condition of the dendrites. Lugaro 

 and Azoulay had already questioned these conclusions, but Soukhanoff 

 under the direction of v. Gehuchten has again put them to the test. 

 From a series of eight experiments upon the effect of acute poisoning 

 by ether, chloroform, and alcohol, upon three species of animals, the 

 author concludes that the varicosity of the dendrites is not at all ab- 

 normal in amount. This renunciation of the territory won by Demoor 

 is interesting in connection with the fact that Demoor himself, at the 

 recent meeting of the physiologists in Cambridge, reiterated and em- 

 phasized his previous statements. Two other experiments, upon the 

 action of trional on guinea-pigs, indicated a marked increase in the 

 number of varicosities. In addition, Soukhanoff verifies the observa- 

 tion of Stefanowska, that invariably associated with the manifestation 

 of retraction is the disappearance of the gemmulte — "appendices piri- 

 formes " — of the dendrites. The author interprets these changes as 

 pathological in character, a specific atrophy, due to disturbances in 

 nutrition. 



The second article of Soukhanoff contains the result of experi- 

 mentation upon the effects of acute and subacute poisoning by arsenic, 

 of thyroidectomy, and of inoculation with hydrophobia, and tuber- 

 culin. A single control rabbit, supposed to be normal, was used for 

 microscopic comparison. The effects of arsenic, as gathered from 

 nine experiments, are, in general, the production of a condition of vari- 

 cosity of the dendrite, with a corresponding disappearance of the gem- 

 mules. The amount of the change is very variable, and not at all pro- 

 portional to the amount of poison injected, nor to the length of the 

 period of poisoning. The lesion, as the author considers it, is diffuse, 

 and not well localized either with reference to the layers or to the super- 

 ficial areas of the cortex. The same, more or less indefinite, result, 

 followed the innoculation of hydrophobia. The injection of tuber- 

 culin, and the experimental hydrophobia, produced the greatest altera- 

 tion in the cortex ; the number of cells affected, and the extent of the 

 change in the dendrites, left no doubt as to the action of these agencies 

 upon them. 



These two articles represent perhaps the most satisfactory experi- 

 mental evidence, save that of Lugaro (1897), for the theory of den- 

 dritic retraction. The constancy with which the changes succeed the 

 action of any given agency, their significance from a physiological 

 standpoint, and their diagnostic importance, are still, however, matters 

 of great doubt. R. weil. 



